AMD issues update about Spectre Variant 4

Today, Microsoft and Google Project Zero researchers have identified a new category of speculative execution side channel vulnerability (Speculative Store Bypass or SSB) that is closely related to the previously disclosed GPZ/Spectre variant 1 vulnerabilities. Microsoft has released an advisory on the vulnerability and mitigation plans.

AMD recommended mitigations for SSB are being provided by operating system updates back to the Family 15 processors (“Bulldozer” products). For technical details, please see the AMD whitepaper. Microsoft is completing final testing and validation of AMD-specific updates for Windows client and server operating systems, which are expected to be released through their standard update process. Similarly, Linux distributors are developing operating system updates for SSB. AMD recommends checking with your OS provider for specific guidance on schedules.

Based on the difficulty to exploit the vulnerability, AMD and our ecosystem partners currently recommend using the default setting that maintains support for memory disambiguation.

We have not identified any AMD x86 products susceptible to the Variant 3a vulnerability in our analysis to-date.

As a reminder, security best practices of keeping your operating system and BIOS up-to-date, utilizing safe computer practices and running antivirus software are always the first line of defense in maintaining device security.